Composition for treating abrasive bodies



Jan. 23, 1945.

COMPOSITION FOR TREATING ABRASIVE BODIES Filed Nov. 2, 1942 INVENTOR.JEFFERSON P404 flucA sr M r w fw flrraewe'rs J. P. BUCKEY 2,367,995-

Patented Jan. 23, 1945 CODIPOSITION FOR TREATING ABRASIVE BODIESJeflerson Paul Buckey, Cleveland, Ohio, assignor to Electronic Products,Inc., Cleveland, Ohio, a

corporation of Ohio Application November 2, 1942, Serial No. 484,192

2 Claims.

invention relates to abrasive bodies such as grinding wheels and thelike, and to a composition for treating such bodies to increase theirabrasive characteristics and durability.

An object of the invention is to provide a novel composition fortreating abrasive bodies for introducing thereinto an activated graphiteand a cement which holds or assists in holding the graphite in suchbodies.

Other objects and advantages of the invention will be apparent from thefollowing description.

In the accompanying sheet of drawing:

Fig. 1 is a plan view of a grinding wheel which has been treatedaccording to my invention; and

Fig. 2 is a sectional view taken through the wheel on line 2-2 of Fig.1.

Although my invention is applicable to the treatment of various abrasivebodies, it is especially suitable for the treatment of grinding wheelsand is hereinafter described in this connection but without any intentto limit the invention in this respect. As will be pointed out more indetail hereinafter, my novel composition and treatment are used tointroduce or incorporate activated graphite into an abrasive wheel in amanner such that the graphite particles will be securely held.Comparative tests show that abrasive wheels having activated graphiteincorporated therein are more durable and economical than untreatedwheels and have superior abrasive characteristics.

The grinding wheels to be treated may be of the usual type orconstruction found in the abrasive art such as a unitary andsubstantially homogeneous bonded body to containing an abrasive grain.The abrasive grain may be crystalline aluminum oxide, crystallinesilicon carbide, crystalline bauxite, emery, quartz, or the like. Thebinder may be any one of suitable synthetic resins, including Bakelite,or it may be a vitreous substance, a silicate, a clay, or rubber. Theinvention is also applicable to the abrasive segments or sections usedin assembled or segmental grinding wheels.

One example of a liquid composition for the treatment of abrasive bodiesaccording to my invention is prepared with the following ingredients:

Parts 2 to 50 5 to 25 Activated graphite Water soluble casein Water as asolvent or vehicle for the casein 100 to 500 As above specified, thegraphite is an activated graphite, and by the term "activated I mean asubstantially chemically pure relatively finely divided porous graphite.The activated graphite maybe obtained from various sources or in variousways such as by the method disclosed in my earlier application, SerialNo. 426,654 filed January 14, 1942, wherein commercial graphite istreated with an electrolytic solvent and subjected to the action of anelectric current.

The above specified ingredients are mixed thoroughly and the resultingliquid composition is heated to boiling temperature, that is,approximately 212 F. The grinding wheels or other abrasive bodies to betreated are immersed in the heated composition and are soaked thereinfor a sufficient period to enable the composition to thoroughlypenetrate the same. The period of treatment may vary considerably,depending upon the density and other characteristics of the abrasivewheels and may vary in duration from fifteen minutes to approximatelyeight hours. During this soaking of the wheels the composition ismaintained at substantially a boiling temperature and is agitated toprevent settling and to insure a, substantailly uniform distribution ofthe activated graphite and casein to all portions of the wheels. Theheating of the composition and the wheels during the soaking operationis important because it opens the pores or interstices of the wheel aswell as the pores of the particles of the bond and the pores of theabrasive grain crystals to admit the composition.

After the wheels have been soaked in the composition for the desiredperiod, they are removed and the liquid is permitted to drain therefrom.In addition to such draining of the wheels, they can, if desired, alsobe subjected to a centrifugal action or spinning operation for expellingadditional liquid therefrom. The treated wheels are then subjected to adrying or baking operation during which the remaining liquid is drivenout. The drying or baking may be carried out at a moderate heat, forexample, 180 F. to 300 F., and for a sumcient period of time to causeall or substantially all of the liquid to be expelled or driven from thewheels in the form of vapor.

Abrasive bodies which have been treated in the manner above describedwill be found to have activated graphite and casein distributedsubstantially uniformly throughout the same. The activated graphite andcasein are carried into the pores or interstices of the wheel and theactivated graphite enters the opened pores of the particles of the bondand the opened pores of the abrasive grain crystals. When the treatedbody has been dried, it is permitted to cool, which causes the pores ofthe abrasive grain crystals and of the particles of the bonding materialto close and grip the particles of activated graphite therein. The driedcasein serves as a cement which tenaciously holds the particles ofgraphite in the pores or interstices of the wheel. The amount ofactivated graphite and casein retained in the treated grinding wheelswill vary more or less and is dependent upon the density of the wheelstherein, the length of beingtreatedtbecharacterotthebondused the periodof treatment, and possibly other (actors. The percentage 0! activatedgraphite retained in the treated wheels is probably in the neighborhoodof 2% o! the weight 0! the wheel. and the amount oi casein retained maylikewise be in the neighborhood 01' 2% ot the weight 01 the treatedwheel.

Ihavedisclosedabovetheuseoicaseinasa cement which assists in holding theactivated graphite in the treated wheels, but various other substancescan be used as the cement or retaining medium for the activatedgraphite. It is desirable that the cement be oil-resistant as well assubstantially non-hygroscopic and substantially non-deliquescent so thatit will not loseitsholding propertlesinthepresenceot moisture and sothat the abrasive wheels can be used in grinding operations where water,oil. or other coolants are employed without resulting in the cementbeing weakened or washed out. The use of casein as the cement for theactivated graphite is especially desirable in the treatment of wheelshaving a bond made of rubber or a rubber-containing substance becausethe water which is used as the solvent or vehicle for the casein doesnot produce a deteriorating eilect on the rubber.

Although casein serves very satisfactorily as the cement for theactivated graphite. I can use as the cement any one of various resins insolution such as shellac, lacquer, and Bakelite. when a resin 01 thiskind is employed as the cement for the activated graphite, the solventshould be a volatile liquid such as alcohol, ether, benzinc, or the likewhich can be driven out of the treated wheel during the drying or bakingoperation. When shellac or one of the other resins i employed as thecement, the amount of the resin and solvent or vehicle used in formingthe composition should be such that the composition will penetrate theabrasive wheel to the desired extent to carry the activated graphitethereinto and will form a tenacious cement for retaining the graphite inthe pores or interstices of the treated wheel after the solvent has beenexpelled. A composition oi. the character just described maybe'preparedwith the iollowing ingredients:

Shellac Approximately 1 quart Alcohol as a solvent or thinner for theshellac Approximately 2 gallons Activated graphite--- 2% to 60% byweight ltmaybedesirabletoaddtothe scribedcompositionsasmallamoimtothydroxideuechnlcalgradeitoprodue ingorrougheningeilectontheparticlesbond embodied in the abrasive wheel. amountofsodiumhydroxidcaddedtothepositionmaybe1rom.l$to.5%byweight, thoughalargerornnallerquantitymaybedependinguponthecharacteristlcs oi the rasivewheelsbeinatreated.Duringthe ingotthewheelsinthecompositionthesubstantially-non-hygroscoplc and substantially non-deliquescent. At thecompletion of the ageing step the treated wheels are ready for use forvarious grinding or abrading operations, and it will be found that whenabrasive bodies have been subjected to the treatment herein disclosed,they will be much more durable than grinding wheels heretofore producedand will have superior abrasive characteristics- The activated graphiteinthe treated wheels acts as an abrasive andasheatconductingmedium aswellasalubricant for the abrasive grain. Grinding wheels which have beentreated as herein disclosed cut much faster than untreated wheels and doso without burning the metal.

While I have described my improvement in considerable detail. it will beunderstood. 0! course. that I intend my invention to include allmodifications and variations coming within the scope of the appendedclaims.

Having thus described my invention. 1 claim:

1. A liquid composition for treating abrasive bodies comprisingactivated graphite, a cement, a solvent for the cement, and sodiumhydroxide.

2. A liquid composition for the treatment oi abrasive bodies comprisingactivated graphite. casein, water, and sodium hydroxide.

N PAUL BUCKEY.

